RLM 81 Version 2 vs Venom Wyrm

How close are they?

ΔE 7.1, close: similar, with a visible difference side by side. Venom Wyrm is more saturated, warmer than RLM 81 Version 2.

Can I use Venom Wyrm instead of RLM 81 Version 2?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Venom Wyrm is more saturated, warmer than RLM 81 Version 2.

Can I use RLM 81 Version 2 instead of Venom Wyrm?

The same difference applies the other way round: RLM 81 Version 2 is more muted, cooler.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.